In recent years, a strong demand for the automated analysis of liquid samples can be observed which is primarily due to the fact that there is an ongoing increase in the number of clinical analyses. Sample analysis typically is based on mixing the samples with one or more reagents for causing analyte-specific reactions, followed by detecting the reaction products to determine absence/presence or concentration of one or more analytes contained therein.
Commercially available analyzers typically make use of pipetting robots for mixing of samples and reagents. Such pipetting robots normally have many fast and nearly continuously moving parts, which may often require frequent maintenance and replacement operations. In addition, conventional analyzers have limited flexibility with regard to the type of the analytical method that can be performed and typically can only be operated with comparably low precision due to the variability of pipetting operations. Furthermore, in such conventional analyzers since reagents are typically exposed to the ambient air, the reagents used therewith may have a reduced shelf life.
Due to low sample consumption, fast analysis times and high sample throughput, many efforts have been made to develop integrated fluidic systems, among these microfluidic systems, for the automated analysis of liquid samples. However, conventional microfluidic systems have many drawbacks since they are limited to predefined workflows and fluid volumes and typically are related to a dedicated type of analytical method. They are provided with a comparably small number of reagent channels and therefore may not be up-scaled according to the demands of the user. Reagents have to be supplied by pipetting operations or via complex tubing to the reagent channels. In addition, microfluidic systems are normally intended for single-use only and therefore are often associated with having comparably large costs.